Multi-core yolk-shell-structured Bi₂Se₃@C nanocomposite as an anode for high-performance lithium-ion batteries

Emerging Bi₂Se₃-based anode materials are attracting great interest for lithium storage because of their high theoretical capacity. Although quite attractive, Bi₂Se₃ still faces the problem of large volume expansion during lithiation/delithiation, leading to poor cycling stability. Herein, a multi-core yolk-shell Bi₂Se₃@C nanocomposite was designed and synthesized via a solvothermal method followed by heat treatment. The as-prepared yolk-shell nanocomposite consists of two parts: several Bi₂Se₃ nanospheres (diameter of approximately 100 nm) as a core, and carbon (thickness of approximately 16 nm) as the shell. Owing to its unique structural features, multi-core yolk-shell Bi₂Se₃@C nanocomposite demonstrates excellent cycling stability with a capacity of 392.2 mA h g^-1 at 0.2 A g^-1 after 100 cycles for lithium-ion batteries (LIBs). A reversible capacity of 416.9 mA h g^-1 can be maintained even at a higher current density of 1 A g^-1 after 1200 cycles. The reason for the superior electrochemical performance was further explored through electrochemical kinetic analysis and theoretical calculations. This work provides an effective strategy for the preparation of multi-core yolk-shell anode materials, and also affords a new method by which to prepare high-performance LIBs.